An anonymous reader shares a report: Within the nightly builds of the Firefox web browser is finally the ability to support playback of Matroska "MKV" content. Enabled just within the Firefox Nightly builds for now or opting in within the media.mkv.enabled preference is the ability to support MKV playback. Initially just AVC/H.264 and AAC within MKV containers are supported but other codec support will be expanded over time. For the past eight years there has been this feature request for supporting Matroska/MKV playback support.Read more of this story at Slashdot.